Datasheet AD7641 (Analog Devices) - 10

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AD7641 Pin No. Mnemonic Type
1
Description
13 D6 DI/O When MODE[1:0] = 0, 1, or 2, this output is used as Bit 6 of the parallel port data output bus. or EXT/INT When MODE[1:0] = 3, (serial mode), serial clock source select. This input is used to select the internally generated (master) or external (slave) serial data clock. When EXT/INT = low, master mode. The internal serial clock is selected on SCLK output. When EXT/INT = high, slave mode. The output data is synchronized to an external clock signal, gated by CS, connected to the SCLK input. 14 D7 DI/O When MODE[1:0] = 0, 1, or 2, this output is used as Bit 7 of the parallel port data output bus. or INVSYNC When MODE[1:0] = 3, (serial mode), invert sync select. In serial master mode (EXT/INT = low), this input is used to select the active state of the SYNC signal. When INVSYNC = low, SYNC is active high. When INVSYNC = high, SYNC is active low. 15 D8 DI/O When MODE[1:0] = 0, 1, or 2, this output is used as Bit 8 of the parallel port data output bus. or INVSCLK When MODE[1:0] = 3, (serial mode), invert SCLK select. In all serial modes, this input is used to invert the SCLK signal. 16 D9 DI/O When MODE[1:0] = 0, 1, or 2, this output is used as bit 9 of the parallel port data output bus. or RDC When MODE[1:0] = 3, (serial mode), read during convert. When using serial master mode (EXT/INT = low), RDC is used to select the read mode. When RDC = high, the previous conversion result is output on SDOUT during conversion and the period of SCLK changes (see the Master Serial Interface section). When RDC = low (read after convert), the current result can be output on SDOUT only when the conversion is complete. or SDIN When MODE[1:0] = 3, (serial mode), serial data in. When using serial slave mode, (EXT/INT = high), SDIN could be used as a data input to daisy-chain the conversion results from two or more ADCs onto a single SDOUT line. The digital data level on SDIN is output on SDOUT with a delay of 18 SCLK periods after the initiation of the read sequence. 17 OGND P Input/Output Interface Digital Power Ground. 18 OVDD P Input/Output Interface Digital Power. Nominally at the same supply as the supply of the host interface (2.5 V or 3 V). 19 DVDD P Digital Power. Nominally at 2.5 V. 20 DGND P Digital Power Ground. 21 D10 DO When MODE[1:0] = 0, 1, or 2, this output is used as Bit 10 of the parallel port data output bus. or SDOUT When MODE[1:0] = 3, (serial mode), serial data output. In serial mode, this pin is used as the serial data output synchronized to SCLK. Conversion results are stored in an on-chip register. The AD7641 provides the conversion result, MSB first, from its internal shift register. The data format is determined by the logic level of OB/2C. In master mode, EXT/INT = low. SDOUT is valid on both edges of SCLK. In slave mode, EXT/INT = high: When INVSCLK = low, SDOUT is updated on SCLK rising edge and valid on the next falling edge. When INVSCLK = high, SDOUT is updated on SCLK falling edge and valid on the next rising edge. 22 D11 DI/O When MODE[1:0] = 0, 1, or 2, this output is used as Bit 11 of the parallel port data output bus. or SCLK When MODE[1:0] = 3, (serial mode), serial clock. In all serial modes, this pin is used as the serial data clock input or output, depending upon the logic state of the EXT/INT pin. The active edge where the data SDOUT is updated depends on the logic state of the INVSCLK pin. 23 D12 DO When MODE[1:0] = 0, 1, or 2, this output is used as Bit 12 of the parallel port data output bus. or SYNC When MODE[1:0] = 3, (serial mode), frame synchronization. In serial master mode (EXT/INT= low), this output is used as a digital output frame synchronization for use with the internal data clock. When a read sequence is initiated and INVSYNC = low, SYNC is driven high and remains high while SDOUT output is valid. When a read sequence is initiated and INVSYNC = high, SYNC is driven low and remains low while SDOUT output is valid. 24 D13 DO When MODE[1:0] = 0, 1, or 2, this output is used as Bit 13 of the parallel port data output bus. or RDERROR When MODE[1:0] = 3, (serial mode), read error. In serial slave mode (EXT/INT = high), this output is used as an incomplete read error flag. If a data read is started and not completed when the current conversion is complete, the current data is lost and RDERROR is pulsed high. Rev. 0 | Page 9 of 28 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM PRODUCT HIGHLIGHTS TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS TIMING SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TERMINOLOGY TYPICAL PERFORMANCE CHARACTERISTICS APPPLICATIONS INFORMATION CIRCUIT INFORMATION CONVERTER OPERATION MODES OF OPERATION TRANSFER FUNCTIONS TYPICAL CONNECTION DIAGRAM ANALOG INPUTS MULTIPLEXED INPUTS DRIVER AMPLIFIER CHOICE Single-to-Differential Driver VOLTAGE REFERENCE INPUT Internal Reference (PDBUF = Low, PDREF = Low) External 1.2 V Reference and Internal Buffer (PDBUF = Low, PDREF = High) External 2.5 V Reference (PDBUF = High, PDREF = High) Reference Decoupling Temperature Sensor POWER SUPPLY Power Sequencing Power-Up CONVERSION CONTROL INTERFACES DIGITAL INTERFACE RESET PARALLEL INTERFACE Master Parallel Interface Slave Parallel Interface 16-Bit and 8-Bit Interface (Master or Slave) SERIAL INTERFACE MASTER SERIAL INTERFACE Internal Clock SLAVE SERIAL INTERFACE External Clock External Discontinuous Clock Data Read After Conversion External Clock Data Read During Previous Conversion MICROPROCESSOR INTERFACING SPI Interface (ADSP-219x) APPLICATION HINTS LAYOUT EVALUATING THE AD7641 PERFORMANCE OUTLINE DIMENSIONS ORDERING GUIDE